Hi,
I have thousands of webpages each represented as serialized tree object
compressed (ZLIB) together (file size varying from 2.5 GB to 4.5GB).
I have to do some heavy text processing on these pages.
What the the best way to read /access these pages.
Method1
***************
1) Write Custom Splitter that
1. uncompresses the file(2.5GB to 4GB) and then parses it(time :
around 10 minutes )
2. Splits the binary data in to parts 10-20
2) Implement specific readers to read a page and present it to mapper
OR.
Method -2
***************
Read the entire file w/o splitting : one one Map task per file.
Implement specific readers to read a page and present it to mapper
Slight detour:
I was browing thru code in FileInputFormat and TextInputFormat. In
getSplit method the file is broken at arbitary byte boundaries.
So in case of TextInputFormat what if last line of mapper is truncated
(incomplete byte sequence). what happens. Is truncated data lost or
recovered
Can someone explain and give pointers in code where and how this
recovery happens?
I also saw classes like Records . What are these used for?
Regds
Amit S
